[web] Add Avatar preview to EmojiAvatarSelectionModal
Summary:
Inspired loosely by CommunityCreationModal.
Depends on D8265
Test Plan:
Looks as expected:
Reviewers: ashoat, ginsu, rohan, inka, michal, kamil
Reviewed By: kamil
Subscribers: tomek
Differential Revision: https://phab.comm.dev/D8266